Atomic cerium-doped CuOx catalysts for efficient electrocatalytic CO2 reduction to CH4

Abstract

Copper (Cu) is widely used in the electrochemical carbon dioxide reduction reaction (ECO₂RR) for efficient methane (CH₄) product. However, the morphology and valence of Cu-based catalysts are usually unstable under reaction conditions. In this work, we prepared Ce-doped MOF-199 precursor (Ce/HKUST-1) and further obtained nanoparticle electrocatalyst Ce/CuO_x-NPs by cyclic voltammetry (CV) pretreatment. The Faradic efficiency of methane (${\text{FE}}_{{\text{CH}}_4}$) maintains above 62% within a broad potential window of 350 mV and the maximum ${\text{FE}}_{{\text{CH}}_4}$ reaches 67.4% with a partial current density of 293 mA/cm² at −1.6 V vs. a reversible hydrogen electrode. Catalyst characterization and theoretical calculations revealed that the unique electronic structure and large ionic radius of Cerium (Ce) not only promoted the generation of key intermediate *CO but also lowered energy barrier of the *CO to *CHO step. This study provides a novel and efficient catalyst for methane production in ECO₂RR and offers profound insights into constructing high performance Cu-based catalysts.